The present invention relates to a sheet and stack feeding mechanism and more particularly to a mechanism for accumulating sheets in a stack by understacking and discharging them as a stack.
In present high speed sheet feeding mechanisms, sheets are fed one by one to an accumulating area where sheets accumulate in a stack. When a certain number of sheets have been deposited in the stack, the entire stack is moved out of the accumulating area to another machine or to another portion of the machine. It is sometimes desirable to accumulate sheets in a stack to feed the sheets one on top of the other and at other times it is desirable to feed the sheets one under the other-commonly called understacking. Hence, it is desirable to have a mechanism which is sufficiently versatile to allow sheets to be fed to the accumulating area from the top or from the bottom. In existing machines, it has been difficult to do this without readjusting the entire machine. In some instances, separate machines are used to feed sheets one on top of each other and to undeerstack sheets. Moreover, existing machines do not have the versatility of permitting sheets to be accumulated one on top of the other or one beneath the other. Existing machines are complex to use and expensive to manufacture and maintain.
The present invention overcomes these difficulties and has for one of its objects the provision of an improved sheet feeding mechanism in which sheets can be accumulated in an accumulating area one under the other.
Another object of the present invention is the provision of an improved sheet feeding mechanism in which a single machine can be easily converted to feed and stack sheets in an accumulating area one beneath the other or one above the other.
Another object of the present invention is the provision of an improved sheet feeding mechanism which is simple to use and inexpensive to manufacture and maintain.
Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to described, or will be indicated in the appended claims and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.